Stepwise recording of original film sound - during sound recording is stored in two stores alternately read out during periods of film feed

摘要

The recording is made in the camera on the film magnetic edge track without misalignment between picture and sound. The sound is also reproduced stepwise using a special play-back device. The sound is during taking in the camera alternately stored for short periods, fractions of a second depending on the frame frequency. The memories are then also alternately read out at a higher speed (e.g. twice). The sound so produced is compressed to at least one film transport step, and is recorded on the edge of the film intermittently moved, by a sound head mounted near the picture gate. While one memory is being filled, the other is read out at a much greater speed during a time interval between beginning and end of a film feed step. Film sound coded in this way is similarly played back by a device with the same transport process, but with the head moved forward by about two frames. This sound is again stored in two stores alternately read out at a slower speed (e.g. half), so that a continuous sound is produced.